Protective coating and method of applying same.



CLINTON r. TOWNSEND, or wasnme'ron, ms'riucror COLUMBIA.

rno'rnc'rrvn comma AND METHOD or A'Prmme same.

Nfo Drawing.-

To all whom it may concern Be it known that I, CLINTON PAUL Town- SEND, a citizen of the United States, residing at Washington, in the District of-Columbia, have invented certain new and useful Improvements in Protective Coatings and Methodsof Applying Same, of which the following is a specification.

'This invention relates-to coating surfaces, theobject of theinvention being the provision of a durable protective coating, applicable to all surfaces and particularly to those of iron and steel.

It has been proposed heretofore to protect ironsurfaces by precipitating upon them a film of copper or other metal, and to apply varnishes, lacquers, paints and the like to the metallic film so produced. I have found that under proper conditions it is practicable to produce in a single operation, upon conductive surfaces as those of iron, steel or other metals, a galvanic deposit of a coating metal and a protective coating for such deposit' This procedure is hlghly advantageous, not only by reason of the simplicity of the process, but because on the one hand the conditions of operation result in the production of an unusually adherent, perfect, non-oxidized and permanent film of the coating metal, and on the other hand the pres- GIIICB of this metal results in a better adherence of the protective varnish or coating. The invention will be described. by means of an illustrative example, but it is to be understood that it is not limited to the materials or proportions therein mentioned.

A mixture of a phenolic body, such as phenol or its homologues, and formaldehyde, or a soluble reaction product thereof, is compounded with a suitable solvent possessing the capability of yielding electrolytically conductive solutions of metalllc salts; of such solvents methyl and ethyl alcohol, phenol and acetone are'examples. To

the solution so prepared, or to either component thereof, is added a metallic salt sol- 'uble in the particular solvent employed.

Thus for example, hydrated or anhydrous cupric chlorid is dissolved in commercial methyl or ethyl alcohol, andthe green solution'so prepared is utilized as a solvent for the condensation product of phenols and formaldehyde, yielding. therewith a dark red or brown varnish which dries quickly'and possesses excellent protective qualities.

This varnish remains clear for long periods,

Specification of Letters Patent.

Patented July 13, 1915.

' Application filed. November 39, 1809. Serial No. 580,644.

is quite permanent in character, and possesses a more or less flllld. consistence accordsation product used. If non-acid varnish of the character be applied, by dipping, brush-- ing to the proportion of solvent and 'conden- 'ing, spraying or otherwise to clean surfaces of iron or steel an almost instantaneous and .very striking -transformation accompanied by a change of color willbe observed, the coating darkening and acquiring a high degree of opacity and luster. If the iron or steel body coated as abov be thereafter partly immersed in alcohol or other solvent for the varnish constituent of the coating, there will be exposedupon the metallic surface a very perfect and integral fi1m of copper, to the unoxidized metallic surface of which film the undissol'ved portions of the protective coating will be found strongly adherent. The presence of this metallic coat or plating is highly advantageous,-in that it not only affords an added protection for the metal against oxidizing or corrosive influences, butit also increases .acidulated with advantage for certain applications, a small proportion of acid, as for I example hydrochloric acid, appearing to result in a quicker deposition of the coating ,80 the adherence of the protective coating and metal, particularly upon slightly oxidized or tarnished metal surfaces; in the use of such acid solutions the rapid darkening above referred to as characteristic of the neutral or basic varnishes is not observed, and the coated surface may present substantiallythe color due to the precipitated metal,

a bright copper-colored coating for instance being obtained with this metal, and'a gray 1 I metallic coating with salts of tin and lead.

In place of copper I may employ salts of all other metals which are soluble in the particu'lar solvent employed and are, in this solution and in presence of the coating material, electronegative to iron or'other metal to be coated or capable of precipitation thereon; Metallic salts should be selected whose acid radicals form with the metal to be coated, salts of this metal which are $01- tin and lead from their chlorid and acetate solutions respectively. As a single further illustrative example, I may mention that if mercuric chlorid be dissolved in an alcoholic solution of a condensation product of phenol and formaldehyde, and the resulting varnish be applied to copper, it will be found that the copper has been amalgamated beneath the coating of varnish and that the latter is very adherent and resistant to mechanical or atmospheric influences.

Without multiplication of examples, it is to be understood that the method is applicable broadly to the production upon metallic surfaces of a composite coating comprising a metallic .film or precipitate and a protective or insulating covering in intimate association therewith. The method is applicable also to the production of composite coatings whereof the coating metal is electr'opositive to the metal to be coated. In this case however it is necessary to employ either an electric current from an external source, or the so-called contact method of precipitation, wherein the metal to be coated is electrically connected with a metal which is electropositive as regards that to be precipitated. In this manner satisfactory deposits of nickel may be formed on iron or copper by precipitation in presence of zinc.

As has been heretofore pointed out by Baekeland (Journal of Industrial and Engineering Chemistry, Vol. I, No. 3, March, 1909), phenols and formaldehyde are capable of reacting, in accordance with the specific proportions employed or in presence of particular condensing agents, to yield a great variety of condensation products, certain of which, and especially those produced in presence of basic condensing agents, are soluble in alcohol, acetone, phenol and similar solvents, but are capable under application of heat of undergoing polymerization, becoming hard, infusible and resistant to all known solvents. I prefer to utilize the valuable properties of these heretofore-described condensation products, inasmuch as it is only necessary to heat the coating in order to effect its transformation into an infusible and insoluble body. The invention is not owever restricted to the employment of such condensation products; instead I may use alcohol-soluble condensation prod-' nets of phenols and formaldehyde which are not capable of hardening under the influence of heat (see Baekeland, Journal of Industrial and Engineering Chemistry, Vol. I, N o. 8, August 1909) or I may use such natural gums or.resins as are applicable to the preparation of varnishes of the class described.

The compositions above referred to are applicable to the coating of other than metallic surfaces, and possess great advantages for particular uses, particularly by reason of the toxic action of the metallic compounds on living organisms. For example they may be applied to the wooden or metal bottoms of ships, to piling and other submerged structures, and in general in all cases where an anti-fouling composition is applicable. For such uses theremay be incorporated with thecondensation products of'phenols and formaldehyde, or with varnishes prepared therefrom, any soluble or insoluble inorganic or organic poison or toxic body capable of preventing or checking the growth oradhesion of barnacles or seaweeds, the attacks of worms or insects, etc. For this purpose the salts or compounds of copper or mercury compounded with those condensation products of phenols and formaldehyde which are capable of transformation under the influence of heat into an insoluble and infusible polymerized product will be found efiicient. The liquid or molten condensation products of phenols and formaldehyde are substantially non-conductive, and While they are solvents for certain metallic salts the solutions so prepared are-not well adapted for purposes of precipitation: for this purpose it is necessary to add a solvent as above described which affords electrolytically conductive solutions of the salts. For applications or uses not involving precipitation, the solvent may be omitted.

The metallic film produced as above described is precipitated under strongly reducing conditions, not only by reason of the presence of the organic solvent, but be cause of the presence of such strong reducing agents as formaldehyde and the reaction products of formaldehyde and phenols. Reducing conditions accelerate the separation of the metal and yield an unoxidized, adherent and relatively permanent metallic film, and are therefore highly advantageous.

In case natural or synthetic gums or resins are employed in place of the several condensation products of phenols and formaldehyde above referred to, strong reducing 2!? As a new article of manufacture, a;

composite article comprising an electrically taneously applied, whereby the metal coating adheres stronglyto the base and to the outer coating.

3. As a new article of manufacture, a com osite article comprising an electrically con uctive base, an outerprotective coating of phenolic condensation product, and an intermediate coating of precipitated metal, said metallic and non-metallic coatings being simultaneously applied, whereby the" metal coating adheres strongly to the base and to'the outer coating.

a. The method of coating electriceliy-conductive objects, which consists in simultaneously forming thereon an adherent coatprotectwe nod-metallic film of phenolic condensation product.

In testimony whereof, I afiix my signature in presence of two witnesses.

F CLINTON TOWNSEND.

Witnesses:

L. H. BREIIELUND, J. Bmcmms'rnm.

ing of precipitated metal, and an overlying 

